Electric Brake Controller EMI Reduction via Phase Zero-Value
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Solution Overview
Problem
Electric brake systems in aircraft generate electromagnetic interference (EMI) emissions due to abrupt current signal changes, which are not effectively mitigated by existing technologies.
Innovation Solution
A controller is designed to maintain one of the three-phase signals at a zero-value, reducing the number of edges in the command signal and thereby minimizing EMI emissions by converting the minimum value of a three-phase signal to zero and sending an edge-reduced command signal to the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional three-phase control signals are used in electric brake systems, then the motor control performance is maintained, but electromagnetic interference (EMI) emissions increase due to abrupt current signal changes
Solution Approach 1:
The controller proactively identifies and maintains one phase signal at zero value before EMI issues occur, preventing abrupt current changes that cause interference. This preliminary positioning of the minimum phase at zero reduces the number of switching edges in the command signal, thereby mitigating EMI emissions while preserving motor control functionality
Solution Approach 2:
The invention changes the parameter of the three-phase control signal by constraining one phase to maintain a zero value. This parameter modification reduces the dynamic range and switching frequency of the command signal, directly lowering EMI emissions while the controller compensates to maintain adequate motor control performance
2Object-affected harmful factors
If the number of edges in the command signal is reduced by maintaining one phase at zero value, then EMI emissions are minimized, but the complexity of the control algorithm increases
Solution Approach 1:
The control system performs self-optimization by automatically identifying which phase should be maintained at zero value based on real-time signal conditions. The controller monitors the three-phase signals and dynamically assigns the zero-value constraint to the appropriate phase, eliminating the need for external intervention or complex manual tuning while achieving EMI reduction
Data Source
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AI summary
A controller (210) for a brake may comprise a tangible, non-transitory memory (214) configured to communicate with the controller (210), the tangible, non-transitory memory (214) having instructions stored thereon that, in response to execution by the controller (210), cause the controller (210) to perform operations comprising receiving (610), by the controller (210), a three-phase signal indicating a first duty cycle for a first phase signal, a second duty cycle for a second phase signal, and a third duty cycle for a third phase signal, determining (630), by the controller (210), a minimum value based upon the first phase signal, the second phase signal, and the third phase signal, and converting (640), by the controller (210), the minimum value to a zero value.